Emissary Reward increase on patch day?

[Udiza-earthen-ring (Udiza)]

From this post:

What to Expect in Visions of N’Zoth and Season 4

As an addition to our Visions of N’Zoth Content Update Notes, here’s an outline of what’s changing over the next three weeks, and when: With scheduled maintenance on January 14: Artifact Knowledge will increase, bringing a player-character with a level 70 Heart of Azeroth to 17500 AP needed to reach 71. N’Zoth Assaults and Horrific Visions begin, and items from those activities can be Corrupted, but will never Warforge/Titanforge. Items from N’Zoth Assaults will scale with your character lev…

It looks like the item level bump happens with the start of Season 4, which is Jan 21st.

@Kaivax

With scheduled maintenance on January 21:

• The new Ny’alotha raid opens for Normal and Heroic difficulties.
• Season 4 begins.
  • Item levels increase by 30 for rewards from seasonal activities (dungeons, PvP, World Quests), and can now be corrupted by N’Zoth.